[UIMA-5597] uv3: FsGenerators may end up all being null

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.0.0SDK-beta
• Fix Version/s: 3.0.1SDK
• Component/s: Core Java Framework
• Assignee: Marshall Schor
• Reporter: Richard Eckart de Castilho
• Created: 30/Sep/17 17:06
• Updated: 15/Jul/19 18:50
• Resolved: 15/Jul/19 18:50

Description

There appears to be a problem with the initialization of the FS generators when many classloaders are involved. uimaFIT configures all component with dedicated resource managers and these are all configured with a parent classloader, causing many UimaClassLoaders to be around in uimaFIT-based setups.

java.lang.IllegalStateException: org.apache.uima.analysis_engine.AnalysisEngineProcessException: Annotator processing failed.    
	at org.apache.uima.fit.pipeline.JCasIterator.next(JCasIterator.java:163)
	at org.apache.uima.fit.pipeline.JCasIterator.next(JCasIterator.java:1)
	at de.tudarmstadt.ukp.dkpro.core.testing.AssertAnnotations.assertTransformedText(AssertAnnotations.java:897)
	at de.tudarmstadt.ukp.dkpro.core.textnormalizer.transformation.RegexBasedTokenTransformerTest.test(RegexBasedTokenTransformerTest.java:45)
        ...
Caused by: org.apache.uima.analysis_engine.AnalysisEngineProcessException: Annotator processing failed.    
	at org.apache.uima.analysis_engine.impl.PrimitiveAnalysisEngine_impl.callAnalysisComponentProcess(PrimitiveAnalysisEngine_impl.java:395)
	at org.apache.uima.analysis_engine.impl.PrimitiveAnalysisEngine_impl.processAndOutputNewCASes(PrimitiveAnalysisEngine_impl.java:297)
	at org.apache.uima.analysis_engine.asb.impl.ASB_impl$AggregateCasIterator.processUntilNextOutputCas(ASB_impl.java:570)
	at org.apache.uima.analysis_engine.asb.impl.ASB_impl$AggregateCasIterator.<init>(ASB_impl.java:412)
	at org.apache.uima.analysis_engine.asb.impl.ASB_impl.process(ASB_impl.java:344)
	at org.apache.uima.analysis_engine.impl.AggregateAnalysisEngine_impl.processAndOutputNewCASes(AggregateAnalysisEngine_impl.java:271)
	at org.apache.uima.analysis_engine.impl.AnalysisEngineImplBase.process(AnalysisEngineImplBase.java:269)
	at org.apache.uima.analysis_engine.impl.AnalysisEngineImplBase.process(AnalysisEngineImplBase.java:284)
	at org.apache.uima.fit.pipeline.JCasIterator.next(JCasIterator.java:142)
	... 26 more
Caused by: java.lang.NullPointerException
	at org.apache.uima.cas.impl.CASImpl.createFsFromGenerator(CASImpl.java:1168)
	at org.apache.uima.cas.impl.CASImpl.createFSAnnotCheck(CASImpl.java:1124)
	at org.apache.uima.cas.impl.CASImpl.createFS(CASImpl.java:1105)
	at org.apache.uima.cas.impl.CASImpl.createAnnotation(CASImpl.java:3919)
	at org.apache.uima.cas.impl.CASImpl.createDocumentAnnotationNoRemoveNoIndex(CASImpl.java:4001)
	at org.apache.uima.cas.impl.CASImpl.createDocumentAnnotationNoRemove(CASImpl.java:3994)
	at org.apache.uima.cas.impl.CASImpl.getDocumentAnnotation(CASImpl.java:4061)
	at org.apache.uima.cas.impl.CASImpl.setDocumentLanguage(CASImpl.java:4202)
	at org.apache.uima.jcas.impl.JCasImpl.setDocumentLanguage(JCasImpl.java:825)
	at de.tudarmstadt.ukp.dkpro.core.api.transform.JCasTransformer_ImplBase.beforeProcess(JCasTransformer_ImplBase.java:81)
	at de.tudarmstadt.ukp.dkpro.core.api.transform.JCasTransformerChangeBased_ImplBase.beforeProcess(JCasTransformerChangeBased_ImplBase.java:57)
	at de.tudarmstadt.ukp.dkpro.core.api.transform.JCasTransformer_ImplBase.process(JCasTransformer_ImplBase.java:127)
	at org.apache.uima.analysis_component.JCasMultiplier_ImplBase.process(JCasMultiplier_ImplBase.java:58)
	at org.apache.uima.analysis_engine.impl.PrimitiveAnalysisEngine_impl.callAnalysisComponentProcess(PrimitiveAnalysisEngine_impl.java:379)
	... 34 more

Usually, this seems to work well in UIMA v2 and UIMA v3. However, presently CAS multipliers seem to be a problem in UIMA v3.

I tried to debug this to some degree based on a unit test in DKPro Core and ended up in the following code in `FSClassRegistry.getGeneratorsForClassLoader(...)`:

       // skip entering a generator in the result if
        //    in a pear setup, and this cl is not the cl that loaded the JCas class.
        //    See method comment for why.
        if (!isPear || jcci.isPearOverride(cl)) {
          r[ti.getCode()] = (FsGenerator3) jcci.generator;
        }   

In this particular unit test, the code is called 3 times.

The first two times when the CAS that is to be passed to the pipeline components is created by the uimaFIT JCasIterator. These first two times appear ok - the feature generators array is filled.

1) cl := sun.misc.Launcher$AppClassLoader
   isPear := false
   jcci.isPearOverride(cl) := true

	FSClassRegistry.getGeneratorsForClassLoader(ClassLoader, boolean, TypeSystemImpl) line: 879	
	TypeSystemImpl.getGeneratorsForClassLoader(ClassLoader, boolean) line: 2630	
	TypeSystemImpl.commit(ClassLoader) line: 1378	
	TypeSystemImpl.commit() line: 1313	
	TypeSystemImpl.<clinit>() line: 2484	
	CASFactory.createTypeSystem() line: 126	
	CASImpl.<init>(TypeSystemImpl, int) line: 885	
	CASImpl.<init>() line: 908	
	CASFactory.createCAS() line: 48	
	CasCreationUtils.doCreateCas(TypeSystem, TypeSystemDescription, TypePriorities, FsIndexDescription[], Properties, ResourceManager) line: 604	
	CasCreationUtils.createCas(Collection<MetaDataObject>, Properties, ResourceManager) line: 292	
	JCasIterator.<init>(CollectionReader, AnalysisEngine...) line: 90	
	JCasIterable.iterator() line: 79	
	JCasIterable.iterator() line: 1	
	AssertAnnotations.assertTransformedText(String, String, String, AnalysisEngineDescription...) line: 897	
	RegexBasedTokenTransformerTest.test() line: 45	

2) cl := org.apache.uima.internal.util.UIMAClassLoader@50378a4 
   isPear := false
   jcci.isPearOverride(cl) := false

	FSClassRegistry.getGeneratorsForClassLoader(ClassLoader, boolean, TypeSystemImpl) line: 879	
	TypeSystemImpl.getGeneratorsForClassLoader(ClassLoader, boolean) line: 2630	
	TypeSystemImpl.commit(ClassLoader) line: 1378	
	CASImpl.commitTypeSystem() line: 1529	
	CasCreationUtils.doCreateCas(TypeSystem, TypeSystemDescription, TypePriorities, FsIndexDescription[], Properties, ResourceManager) line: 613	
	CasCreationUtils.createCas(Collection<MetaDataObject>, Properties, ResourceManager) line: 292	
	JCasIterator.<init>(CollectionReader, AnalysisEngine...) line: 90	
	JCasIterable.iterator() line: 79	
	JCasIterable.iterator() line: 1	
	AssertAnnotations.assertTransformedText(String, String, String, AnalysisEngineDescription...) line: 897	
	RegexBasedTokenTransformerTest.test() line: 45		

The third time in the FlowController. This time `isPear` is `true` causing the FS generators array to be all null. Mind, I'm not using PEARs, I only set the parent classloader for the resource managers, no custom classpath URLs.

3) cl = org.apache.uima.internal.util.UIMAClassLoader@4b2bac3f
   isPear := true
   jcci.isPearOverride(cl) := false

	FSClassRegistry.getGeneratorsForClassLoader(ClassLoader, boolean, TypeSystemImpl) line: 891	
	TypeSystemImpl.getGeneratorsForClassLoader(ClassLoader, boolean) line: 2630	
	CASImpl$SharedViewData.switchClassLoader(ClassLoader) line: 724	
	CASImpl.switchClassLoaderLockCasCL(ClassLoader) line: 3568	
	FlowControllerContainer.computeFlow(CAS) line: 226	
	ASB_impl$AggregateCasIterator.<init>(ASB_impl, CAS) line: 406	
	ASB_impl.process(CAS) line: 344	
	AggregateAnalysisEngine_impl.processAndOutputNewCASes(CAS) line: 271	
	AggregateAnalysisEngine_impl(AnalysisEngineImplBase).process(CAS) line: 269	
	AggregateAnalysisEngine_impl(AnalysisEngineImplBase).process(JCas) line: 284	
	JCasIterator.next() line: 142	
	JCasIterator.next() line: 1	
	AssertAnnotations.assertTransformedText(String, String, String, AnalysisEngineDescription...) line: 897	
	RegexBasedTokenTransformerTest.test() line: 45